Royal Baby Fans Gather Outside St. Mary's Hospital, Buckingham Palace

With Kate Middleton currently in labor, royal baby fever has reached an all-time high. Reporters have been camped outside St. Mary's Hospital in London for weeks, and now hundreds of fans have joined the journalists outside the Lindo Wing, where the Duchess of Cambridge will give birth to the third in line to the British throne. Middleton and Prince William, both 31, arrived quietly through the Mary Stanford entrance around 6 a.m. on Monday, July 22.

"It's absolutely buzzing outside the Lindo Wing: TV outlets from every corner of the globe, almost 100 photographers on ladders," says OmidScobie, UsWeekly's European Bureau Chief. "Kate's been in labor over 10 hours now and everyone's on tenterhooks."

Members of the public gather outside The Lindo Wing as The Duchess Of Cambridge goes into labour at St Mary's Hospital on July 22, in London, England. Credit: Peter Macdiarmid/Getty Images

Scobie continues, "Everyone is waiting for that moment that the birth bulletin is carried out of the main entrance and driven to Buckingham Palace. Of course, that means between now and then every photographer is jumping to attention at the first sight of anyone leaving the building with an envelope in their hands. It's tense."

Several hundred admirers have also gathered outside Buckingham Palace as they await the arrival of the couple's firstborn. Locals and tourists alike dressed in patriotic garb, arriving with flowers, cakes and other presents. To keep the crowd under control, police officers instructed the media to stay within fenced areas. (As previously reported, the official announcement of the royal baby's birth will be placed on an easel inside the palace gates.)

Fans who aren't in London are getting in on the action via social media. "Wow, it's been a long and hot day for Kate to be in labour!" one Twitter user wrote. "Let's hope the baby arrives soon!" Said another, "It's so weird to think that right now Kate Middleton is giving birth to the future king or queen."